Boeing 737 "Classic" - 300 / 400 / 500 cockpit diagram showing both mechanical and digital engine instruments. The 300/400/500 series where the first 737 to be fitted with Electronic Flight Displays (EFIS) as the Primary Flying Display (PFD) and Navigation Display (ND). This drawing is available as both a printed A0 sized poster and as a digital download (pdf) from shop.aviatastraining.com